1. Field of the Invention
This invention relates to improvements in a continuously variable transmission provided with a mechanical feedback mechanism for speed-change of a vehicle, and more particularly to a cooling structure for an actuator for speed-change control, in the mechanical feedback mechanism.
2. Description of the Prior Art
Hitherto, a variety of mechanical feedback mechanisms to be used for speed-change in a continuously variable transmission in a vehicle have been proposed and put into practical use. One of these mechanical feedback mechanisms is disclosed in Japanese Patent Laid-open Publication No. 2001-260678. In the technique of this publication, the continuously variable transmission is provided with a mechanical feedback mechanism in which a motor for speed-change control, a speed-change control valve and a pulley sensor are linked to each other by a linking member. The linking member is under necessity of linking the pulley sensor located at the side of a power train and the speed-change control valve located within a control valve assembly. Therefore, the motor for speed-change control is disposed to a side surface of the control valve so as to be located under an oil surface or level inside the continuously variable transmission in consideration of assembly efficiency of the mechanical feedback mechanism and a cooling performance to the motor for speed-change control.
However, in the above conventional technique, the motor for speed-change control is limited in arrangement, and therefore it is difficult to ensure the compactness of a transmission unit.